caa a22 4500 605545901 CHVBK 20210128100938.0 cr unu---uuuuu 210128e20150401xx s 000 0 eng 10.1007/s00723-014-0638-z doi (NATIONALLICENCE)springer-10.1007/s00723-014-0638-z EPR Analysis of Imidazole Binding to Methanosarcina acetivorans Protoglobin [Elektronische Daten] [Sabine Van Doorslaer, Martje van den Bosch, Lesley Tilleman, Sylvia Dewilde] Protoglobins form an unusual class of globin proteins with surprising structural features, such as a highly ruffled heme. Electron paramagnetic resonance spectra of the frozen solution of the ferric imidazole complex of Methanosarcina acetivorans protoglobin reveal the existence of two low-spin ferric heme complexes. Hyperfine sublevel correlation spectroscopy was used to study the imidazole complex of this protoglobin as well as the imidazole complex of horse heart myoglobin for comparison. The spin Hamiltonian values obtained for the dominant contribution of the imidazole-ligated protoglobin agree with a heme conformation in which the plane of the exogenous imidazole is turned more than 30° versus the imidazole plane of the proximal histidine ligand. In turn, the electron paramagnetic resonance data of the minority complex indicate a second conformer, in which the two ligand planes are aligned almost parallel to each other with a lengthened iron-nitrogen bond for the exogenous imidazole ligand. Springer-Verlag Wien, 2015 Van Doorslaer Sabine BIMEF Laboratory, Department of Physics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut van den Bosch Martje BIMEF Laboratory, Department of Physics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut Tilleman Lesley PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut Dewilde Sylvia PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut Applied Magnetic Resonance Springer Vienna 46/4(2015-04-01), 421-433 0937-9347 46:4<421 2015 46 723 https://doi.org/10.1007/s00723-014-0638-z text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00723-014-0638-z text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Van Doorslaer Sabine BIMEF Laboratory, Department of Physics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut NATIONALLICENCE 700 1- van den Bosch Martje BIMEF Laboratory, Department of Physics, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut NATIONALLICENCE 700 1- Tilleman Lesley PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut NATIONALLICENCE 700 1- Dewilde Sylvia PPES Laboratory, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium aut NATIONALLICENCE 773 0- Applied Magnetic Resonance Springer Vienna 46/4(2015-04-01), 421-433 0937-9347 46:4<421 2015 46 723